Hypothermia & the ACLS algorithm

There are a multitude of definitions and cut-off values for the varying degrees of hypothermia. Mild hypothermia (34 - 35C or 93.2 -95F) is considered the excitation phase wherein shivering occurs and cardiac output increases. In moderate hypothermia (30 - 34C or 86 – 93.2F) the adynamic phase, cardiac output begins to drop. This progresses to the complete cardiovascular shutdown seen in severe hypothermia (30C. All medications should be withheld until temperature is >30°C via active internal rewarming. Extracorporeal membrane oxygenation (ECMO) provides rapid rewarming, increasing core temperature by 1-2C every 15 minutes. If ECMO is unavailable, other modalities of internal rewarming should be performed including peritoneal lavage and pleural lavage with warm saline through chest tubes. Providers ought to be aware of rewarming phenomenon such as “afterdrop,” theorized to occur upon rewarming of peripheral tissues. Vasodilatation causes cooler blood in the extremities to circulate to the body core, averaging out to a cooler body temperature overall. Lastly, a patient is not dead until they are “warm and dead” at 32C (92F), considering a higher threshold in pediatric patients with a more responsive myocardium.

Comments

Let me point out what no-one seems able to come out and say: you have to do chest compressions for hours while rewarming the patient. The ER waitingt room will overflow into the parking lot. I am trying to come up with strategies to be more efficient with my next hypothermic.

Intravascular temperature management strategies like using an Alsius ThermoGard catheter for endovascular rewarming must also be considered. ECMO is great if you got it, but how many of us have ECMO capability lying around at 2 AM on a Sunday in the ED when we need it. With the ThermoGard catheter and warming unit, you are in much more familiar territory and well on your way to normothermia.